This competing continuation proposal has both a basic research focus and an applied clinical nursing focus. Both foci have emerged from research in the previous years. One arm of the basic research is to begin an investigation into a radically new area of physiological or voice measurement termed chaotic variability, and to determine if this new nonlinear type of variability is altered by stress-anxiety, as suggested by a pilot study. Should this be confirmed by the investigation proposed, this would be the first scientific evidence of alterations in chaotic variability due to stress-anxiety and the basis for a completely new axis of measurement that could be used with various physiological or voice variables to measure stress-anxiety and possibly serve as a basis for a new noninvasive method for assessing subtle or early alterations in cardiac or skeletal muscle functions (e.g., using existing cardiac monitors, audiotaped voice samples). The other arm of the basic research focus is to refine a valid and reliable vocal measure of stress-anxiety that is independent of language content and can be used as a noninvasive, moment-to-moment measure of stress-anxiety in future clinical nursing research. The clinical focus follows up on this latter arm of basic research by testing: (1) whether such nonlinguistic voice measures can differentiate between utterances of women in advanced labor which reflect stress-anxiety and those which reflect physical effort, and (2) testing whether the findings can be used in a scientifically based program to teach novice nurses to make such discriminations. Such differentiations are clinically important to the nurse's assessment of the woman's needs and of the progress from active to the expulsive phase of labor so as to adjust intervention appropriately. The aims for this research are as follows: (1) to develop a more refined valid, reliable mathematical model of tenseness to be used as a measure of stress-anxiety, including use in Aims 3 and 4; (2) to ascertain the presence of chaotic variability in jitter, shimmer and/or forehead muscle activity (EMG); and to determine the construct validity and reliability of such chaotic variability of any of these variables and/or the chaotic variability of heart rate; (3) to explore the clinical applicability of those voice variables emerging from the first three years of study and Aim 1 as reflecting stress-anxiety of controlled vowel phonations, as potential indicators of stress-anxiety in spontaneous utterances in a clinical setting by (a) describing those voice variables which characterize stress-anxiety and those which characterize effort in the utterances of women during advanced labor, and by (b) identifying those nonlinguistic voice properties, or combinations that can differentiate between utterances reflecting stress-anxiety and those reflecting physical effort in women during advanced labor; and (4) to utilize those objectively measured differences in nonlinguistic voice variable which emerge from Aim 3 to develop audiotapes that could be used to teach students of nursing and novices to differentiate between those utterances of women in advanced labor which reflect stress-anxiety and those which indicate physical effort and to evaluate the effectiveness of such audiotapes.